KNOXVILLE, Tenn. — Social media app TikTok is under scrutiny by U.S. leaders, including Tennessee Senator Marsha Blackburn.

Blackburn's open letter on Tuesday is the latest in a series of calls to investigate the video-sharing app because of its Chinese ownership. The video-sharing app is owned by ByteDance, a Chinese technology company.

In a Tuesday press release, Blackburn's office said the letter "told TikTok it must put an end to Chinese-linked efforts to collect data from American children."

TikTok is a social media app where users share short videos, typically involving comedy and lip-syncing. 

Blackburn's letter follows multiple reports that said the U.S. government has launched a national-security review of the app.

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Blackburn's letter was addressed to Alex Zhu, an app designer who created TikTok's original version Music.ly. He is now the head of TikTok.

Blackburn said TikTok "is paving the way for the Chinese government to gain unfettered and unsupervised access to our children’s lives." 

She asked Zhu to provide written responses to several questions about the app's demographics and data-sharing policies by Nov. 26 of this year.

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After the initial calls for investigation in late October, TikTok released a statement about its policies. The company said it stores U.S. user data in the United States and none of its data is subject to Chinese law. 

"Our US moderation team, which is led out of California, reviews content for adherence to our US policies – just like other US companies in our space. We are not influenced by any foreign government, including the Chinese government; TikTok does not operate in China, nor do we have any intention of doing so in the future," the statement read.